The development of microelectromechanical systems (MEMS) technology has enabled manufacturers to produce accelerometers sufficiently small to fit into portable electronic devices. Such accelerometers can be found in a limited number of commercial electronic devices such as cellular phones, game controllers, and portable computers.
Generally, devices that utilize an accelerometer to measure motion to detect steps or other activities require the user to first position the device in a specific orientation. In some devices, the required orientation is dictated to the user by the device. In other devices, the beginning orientation is not critical, so long as this orientation can be maintained. However, it can be difficult to keep a portable device in a fixed orientation.